/Engine/Plugins/Animation/IKRig/Source/IKRigEditor/Public/RigEditor/SIKRigHierarchy.h
void AddSelectedItemFromViewport ( const [FName](API\Runtime\Core\UObject\FName) & ItemName, [IKRigTreeElementType](API\Plugins\IKRigEditor\RigEditor\IKRigTreeElementType) ItemType, const bool bReplace )